File extensions start with character 'T'
| File Type | Category | File Format | |
|---|---|---|---|
| .t | Development Files | Turing Source Code File | |
| .t01 | Data Files | TaxCut 2001 File | |
| .t02 | Data Files | TaxCut 2002 File | |
| .t03 | Data Files | TaxCut 2003 File | |
| .t04 | Data Files | TaxCut 2004 File | |
| .t05 | Data Files | TaxCut 2005 Tax Return | |
| .t06 | Data Files | TaxCut 2006 Tax Return | |
| .t07 | Data Files | TaxCut 2007 Tax Return | |
| .t08 | Data Files | TaxCut 2008 Tax Return | |
| .t09 | Data Files | At Home 2009 Tax Return | |
| .t10 | Data Files | At Home 2010 Tax Return | |
| .t2 | Data Files | Textease 2000 File | |
| .t2k | Document Files | Teach2000 Document | |
| .t2ks | Data Files | Teach2000 Exam Results File | |
| .t2kt | Data Files | Teach2000 Exam File | |
| .tab | GIS Files | MapInfo TAB File | |
| .tar | Archive Files | Consolidated Unix File Archive | |
| .tardist | Data Files | TAR Distribution Archive | |
| .tax | Data Files | TurboTax Tax Return | |
| .tax08 | Data Files | TurboTax 2008 Tax Return File | |
| .tax09 | Data Files | TurboTax 2009 Tax Return File | |
| .tax10 | Data Files | TurboTax 2010 Tax Return File | |
| .tax11 | Data Files | TurboTax 2011 Tax Return File | |
| .tax2008 | Data Files | TurboTax 2008 Tax Return | |
| .tax2009 | Data Files | TurboTax 2009 Tax Return | |
| .tax2010 | Data Files | TurboTax 2010 Tax Return | |
| .tax2011 | Data Files | TurboTax 2011 Tax Return | |
| .taz | Compressed Files | Tar Zipped File | |
| .tb | Data Files | Tabbery Tab File | |
| .tbk | Backup Files | ToolBook File | |
| .tbl | Data Files | StarCraft Information Table | |
| .tbn | Raster Graphics Files | XBMC Thumbnail Image | |
| .tbz | Compressed Files | Bzip Compressed Tar Archive | |
| .tbz2 | Compressed Files | Tar BZip 2 Compressed File | |
| .tcc | Data Files | TimeCalc Classic Data File | |
| .tcx | Data Files | Training Center Database File | |
| .tda | Data Files | Palm To-Do File | |
| .tdb | Backup Files | eBay Turbo Lister Backup File | |
| .tde | Data Files | Tableau Data Extract File | |
| .tdf | Text Files | Guide Text Definition File | |
| .tdm | Data Files | LabVIEW Binary Measurement File | |
| .tdt | Data Files | THOR Data Tree File | |
| .tdz | Firmware Update Files | Drobo Firmware File | |
| .te3 | Data Files | WinTrack Object File | |
| .tec | Multiple Use Files | TECkit Compiled Mapping File | |
| .tef | Data Files | TablEdit Tablature | |
| .template | Text Files | Apple Pages Template | |
| .tet | Data Files | Textease CT Template | |
| .tex | Text Files | LaTeX Source Document | |
| .text | Text Files | Plain Text File | |
| .texturepa | Data Files | Minecraft Zip Archive Files | |
| .tfa | Data Files | TreeSoft CashFlow Analysis Data File | |
| .tfm | Font Files | TeX Font Metric File | |
| .tfx | Development Files | Traffix Traffic Analysis Software File | |
| .tg | Audio Files | TuxGuitar Document | |
| .tg4 | Raster Graphics Files | Tiled Group 4 Raster Image File | |
| .tga | Raster Graphics Files | Targa Graphic | |
| .tgf | Data Files | Trivial Graph Format File | |
| .tgz | Archive Files | Gzipped Tar File | |
| .themepack | Configuration Files | Windows 7 Theme Pack | |
| .thm | Raster Graphics Files | Thumbnail Image File | |
| .thp | Text Files | TurboTax Text String | |
| .thr | Data Files | Pro/ENGINEER File | |
| .tif | Raster Graphics Files | Tagged Image File | |
| .tjp | Data Files | TaskJuggler Project File | |
| .tk3 | eBook Files | TK3 Multimedia eBook | |
| .tkfl | Data Files | TKLinks Saver Favorite Links File | |
| .tl5 | Data Files | Timeliner 5 File | |
| .tlb | Multiple Use Files | OLE Type Library | |
| .tld | Development Files | Tag Library Descriptor File | |
| .tlk | Game Files | BioWare Aurora Engine Talk Table File | |
| .tls | Multiple Use Files | TuneUp Utilities Logon Screen | |
| .tlz | Compressed Files | Tar LZMA Compressed File | |
| .tlzma | Compressed Files | LZMA Compressed Tar Archive | |
| .tm | Text Files | TeXmacs Document | |
| .tmp | Backup Files | Temporary File | |
| .tmr | Data Files | Apimac Timer Document | |
| .tmw | Data Files | Translation Memory Data File | |
| .tmx | Data Files | Translation Memory Exchange File | |
| .tng | Vector Graphics Files | Namo WebCanvas Vector Graphic File | |
| .to4 | Data Files | Top 4 Compressed Data File | |
| .toc | Multiple Use Files | Eudora Table of Contents | |
| .tol | Data Files | AOL Tool File | |
| .top | CAD Files | TopSolid Design Document | |
| .topc | Data Files | TopicCrunch Project File | |
| .torrent | Multiple Use Files | BitTorrent File | |
| .tpb | Data Files | GROMACS Binary Input File | |
| .tpc | Text Files | Topic Connection Placeholder | |
| .tpf | Font Files | Transit NXT Pack Translation File | |
| .tpl | Multiple Use Files | Document Template | |
| .tps | Database Files | Clarion TopSpeed Data File | |
| .tpz | eBook Files | Kindle Topaz eBook File | |
| .tr3 | eBook Files | TomeRaider eBook File | |
| .tra | Data Files | WinTrack Railroad Track File | |
| .trd | Data Files | TrID Definitions Package | |
| .trk | Data Files | CompeGPS Land Track File | |
| .trm | Data Files | FTR Media File | |
| .trp | Digital Video Files | HD Video Transport Stream | |
| .trs | Data Files | Rosetta Stone Language Data File | |
| .trx | Development Files | Visual Studio Test Results File | |
| .ts | Digital Video Files | Video Transport Stream File | |
| .tst | Data Files | TestPoint Test File | |
| .tsv | Data Files | Tab Separated Values File | |
| .tt10 | Data Files | TurboTax Canada 2010 Tax Return | |
| .tt11 | Data Files | TurboTax Canada 2011 Tax Return | |
| .ttc | Font Files | TrueType Font Collection | |
| .ttf | Font Files | TrueType Font | |
| .ttk | Data Files | Catalyst Translation Toolkit | |
| .twb | Data Files | Tableau Workbook File | |
| .twbx | Data Files | Tableau Packaged Workbook | |
| .txa | Data Files | Midas ViewPoint Text Array List | |
| .txd | Dictionary Files | Game Texture Dictionary | |
| .txf | Data Files | Tax Exchange Format | |
| .txn | Data Files | MySpaceIM Conversation Log File | |
| .txt | Text Files | Plain Text File | |
| .txz | Archive Files | XZ Compressed Tar Archive |